The present invention relates to a method for alignment of vehicle bodies and frames utilizing a rectangular beam frame having attachment means for rigidly supporting the vehicle while carrying out alignment operations, which frame also serves as the basis for securing various alignment devices required for said alignment operations, said frame including at least two beam members extending longitudinally of the vehicle to be aligned and at least two crossing transverse beam members, which are placed in superposed relationship at the crossing points preferably with the transverse beam members uppermost and joined by securing means located in vertical longitudinal slots in said beam members so as to be variably adjustable along the length thereof. Vehicle alignment methods utilizing vehicle frame alignment apparatus of this kind have been known for several decades and have generally comprised the use of a rigid frame of steel beams. Mainly said frame also has been stationary, either sunk into a moulded floor or other ground or supported from a ground by a base, such as in the form of a center pillar. In its turn, the vehicle has been mounted on said frame by securing means, and on the frame also has been mounted the alignment apparatus, mostly of hydraulic type, which are required for carrying out the alignment operations.
Prior art methods utilized securing means for securing the vehicle to the frame consisting of simple posts or trestles bolted directly to the chassi frames of the vehicles at that time. in the alignment of modern vehicle bodies of self-supporting type it became, however, more and more difficult to obtain such load-carrying points on the vehicle body which could be utilized for the attachment of the vehicle on the alignment frame during the alignment operation. This implied a restriction to the use mostly of the details of the vehicle body which are particularly reinforced and which have great load-carrying capacity, such as the front wheel suspension mountings, the rear wheel spring mountings and the like. In its turn, this has required that every car manufacturer has been forced to state for each model and particular car type a number of such points or locations in the vehicle which are suited for such attachment purposes. In connection therewith, it is also necessary that the car manufacturer mention suitable points in the body, particularly on the underside of the bottom plate from which measurements can be made for the determination of the deformations of the body, if any, and thus also for insuring that the vehicle, after alignment, has regained its original shape corresponding to the drawings of the manufacturer, so as to fulfill all traffic safety requirements.
As a consequence, the manufacturer of alignment apparatus also must manufacture and market a particular set of securing means or fixtures for each car make, type and model so as to allow the use of the alignment apparatus for aligning said vehicles. In many cases, it has also been necessary to manufacture individually for each vehicle make, type and model particular checking fixtures for measuring the extent of the damage to the vehicle and the required alignment and checking thereof when finished. The costs for each such set of fixtures etc. is relatively great and can amount to $900 - $1200. However, the economically profitable period for carrying out more extensive alignment operations on modern vehicles is only about 3-5 years and not even the largest alignment work shops have the opportunity to carry out more than a restricted number of such operations on each individual vehicle type and model, and thus it is obvious that the procuring of all these sets of fixtures for each model of each vehicle make and type is a very heavy investment in view of the short useful period.
Certainly, said prior art method utilizing alignment apparatus of permanent and stationary type could be used for most, but not all, types of body damage; nevertheless, certain very heavily wrought bodies could not be attached and aligned in a satisfactory manner also, such apparatus is voluminous and cumbersome to use and therefore not so well suited to modern, highly rationalized and mechanized and piecerated operations in modern auto repair shops. Therefore, there has been a tendency for several years to modernize and improve the prior alignment apparatus by means of a number of various provisions. Thus, the beam frame has been made separate from its permanent mounting and instead been made movable on rollers on the floor so as to be able to be moved at will. For the attachment of the vehicle bodies to the beam frame, attempts had been made to eliminate the expensive individual fixtures for each vehicle model and to utilize instead more universally adaptable securing means of clamping jaw type, which are attached to the weld rim along the sides of the vehicle, i.e. the so-called door sills. Said portions of the vehicle bodies now have increased strength, because of the need to provide torsional stiffness and load-carrying capability of the body and therefore they can be advantageously utilized for attachment purposes. Many times, however, the locations for said attachment are more or less heavily damaged and therefore it is still difficult to utilize said securing means.
Moreover, the beam frame utilized in this method has been provided with attachment points for support beams for supporting drawing alignment devices in the form of hydraulic or pneumatic pressure cylinders or the like. Said support beams have been mounted by means of clamping connections or bolts passed through uniformly spaced holes in the flanges of the beams or the like.
Another difficulty in connection with alignment apparatus used in prior art methods has been the checking of the measures of the vehicle both before the alignment operation for determining the extent of the deformations of the vehicle and often an alignment operation to determine that the alignment has been correctly made. When particular checking fixtures were to be avoided for such measuring, mainly only two other measuring methods have been available, namely either a projection of the reference points of the vehicle to the floor by means of a plummet or measuring by means of adjustable measuring rods, i.e. so-called telescopes. A measuring of the whole underframe of the car by means of such telescopes is very cumbersome and thus expensive, while a plummet measuring in spite of greatest carefulness still turns out to be afflicted with substantial errors. To obtain a very high degree of precision in measurement, a special measuring apparatus must be used, but this requires of course a cumbersome moving of the work between measuring apparatus and alignment apparatus several times. Recently optical measuring devices have been developed, particularly of the laser kind, which have made it highly desirable to carry out the control measurement directly on the alignment apparatus, especially in connection with the carrying-out of the very alignment operations. This cannot be done, however, utilizing the prior art alignment apparatus due to its structural design and the method for its use. Particularly, it has been especially difficult to measure exactly the vertical deformations of the vehicle since no measuring devices suitable for this purpose have existed.